The present invention relates generally to the field of database management, and more particularly to database upgrades.
In database systems, a database refers to a collection of data that may include schemas, tables, queries, reports, views and other objects. The data are generally organized such that the data are able to be easily accessed, managed, and updated. A database catalog of a database instance consists of metadata in which definitions of database objects such as base tables, views (virtual tables), synonyms, value ranges, indexes, users, and user groups are stored.
Among many operations of databases, an upgrade is an important database operation to keep a database up-to-date. As part of database upgrade, database catalog objects need to be updated. Modifications of database catalog objects generally include: (i) addition of one or multiple new system catalog tables; (ii) addition of new columns in existing system catalog tables; (iii) removal of some columns from existing system catalog tables; and/or (iv) altering column definitions of existing system catalog tables.